The quality of any chord (e.g., major, minor, or dominant) can be changed to another quality as long as the root remains the same as shown in the box below.

Original Chord Quality

Chord Quality Substiutions

Major

Minor or Dominant

Minor

Major or Dominant

Dominant

Major or Minor

Chord quality changes were used to create the two examples shown below. The replacement of a major chord by its minor quality, or vice versa, is referred to as a parallel major/minor substitution. Two examples of this type of substitution are shown below. The first example changes the quality of the F chord to Fm transforming the doo-wop progression into the main verse progression to Sleep Walk (Santo & Johnny  1959). The second example changes the quality of the G chord to Gm transforming the rock and roll progression into the Louie Louie (Kingsmen  1963) progression. (Excerpt from Chord Progressions For Songwriters)